Located near Lincoln's Inn in Barbican Street, Lavender House is a large, wealthy-looking building, though its exterior is quite unremarkable, with no more than two marble tubs of lavender plants to distinguish it from its neighbors. Velvet curtains conceal the goings-on within, though one can hear voices through the windows. It does not face Barbican Street, but rather backs up to it; the front entrance faces a small private park.
Events of the Novels
Lord John visits Lavender House while investigating Joseph Trevelyan's affair. He meets Percy Wainwright there briefly before interrogating Dickie "Mother" Caswell for information about a lady in a green dress. He ends the evening with an anonymous young man, seeking oblivion.
Through Hubert Bowles it's revealed that the day before his death, Timothy O'Connell had gone to Lavender House seeking a person named Meyer. Bowles believes this Meyer to be a spy master that O'Connell was going to sell information to. However, to Caswell's knowledge – or so he says – there is no such Meyer associated with the house.